Recycle damaging contaminants

Recycling byproducts or contaminants which damage the reactor. When recycling unconverted feed material, it is possible that... 

The amount of stabilizer in a recycled material that is consumed during the first application has to be at least replaced, if comparable service and quality requirements have to be fulfilled. However, this is usually not sufficient recycled plastics from short-term applications, such as food packaging, certainly do not contain enough residual stabilizers or light stabilization to satisfy subsequent application in long-term service. Pre-damage and the molecular changes induced, mainly by oxidation, as well as the influence of mixtures and contaminations also reduce the stability of recycled compounds, so that post-stabilization may have to take these influences into account [533]. 

Glass bead and walnut shell blasting are very effective in removing metallic surface contamination without damaging the surface. It is sometimes necessary to resort to blasting with clean sand to restore heavily contaminated surfaces such as tank bottoms, but care must be taken to be certain the sand is truly clean, is not recycled, and does not... 

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